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Convert8To16 use VPSRLW instead of VPMULHUW for better lunarlake performance

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- MCA says old version was 4 cycles and new version is 2.5 cycles/loop
- lunarlake is the only known cpu
mca -mcpu=lunarlake 100 iterations

Was vpmulhu
  Iterations:        100
  Instructions:      1200
  Total Cycles:      426
  Total uOps:        1200

  Dispatch Width:    8
  uOps Per Cycle:    2.82
  IPC:               2.82
  Block RThroughput: 4.0

Now vpsrlw
  Iterations:        100
  Instructions:      1200
  Total Cycles:      279
  Total uOps:        1400

  Dispatch Width:    8
  uOps Per Cycle:    5.02
  IPC:               4.30
  Block RThroughput: 2.5

Bug: None
Change-Id: I5a49e1cf1ed3dfb59fe9861a871df9862417c6a6
Reviewed-on: https://chromium-review.googlesource.com/c/libyuv/libyuv/+/6697745
Reviewed-by: richard winterton <rrwinterton@gmail.com>
This commit is contained in:
Frank Barchard 2025-08-01 16:19:12 -07:00
parent cdd3bae848
commit 48943bb378
5 changed files with 26 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
source/row_gcc.cc
View File

@ -5106,31 +5106,30 @@ void Convert8To16Row_AVX2(const uint8_t* src_y,
uint16_t* dst_y,
int scale,
int width) {
asm volatile(
"vmovd %3,%%xmm2 \n"
"vpbroadcastw %%xmm2,%%ymm2 \n"
const int shift = __builtin_clz(scale) - 15;
asm volatile("vmovd %3,%%xmm2 \n"
// 32 pixels per loop.
LABELALIGN
// 32 pixels per loop.
LABELALIGN
"1: \n"
"vmovdqu (%0),%%ymm0 \n"
"vpermq $0xd8,%%ymm0,%%ymm0 \n"
"add $0x20,%0 \n"
"vpunpckhbw %%ymm0,%%ymm0,%%ymm1 \n"
"vpunpcklbw %%ymm0,%%ymm0,%%ymm0 \n"
"vpmulhuw %%ymm2,%%ymm0,%%ymm0 \n"
"vpmulhuw %%ymm2,%%ymm1,%%ymm1 \n"
"vpsrlw %%xmm2,%%ymm0,%%ymm0 \n"
"vpsrlw %%xmm2,%%ymm1,%%ymm1 \n"
"vmovdqu %%ymm0,(%1) \n"
"vmovdqu %%ymm1,0x20(%1) \n"
"add $0x40,%1 \n"
"sub $0x20,%2 \n"
"jg 1b \n"
"vzeroupper \n"
: "+r"(src_y), // %0
"+r"(dst_y), // %1
"+r"(width) // %2
: "r"(scale) // %3
: "memory", "cc", "xmm0", "xmm1", "xmm2");
: "+r"(src_y), // %0
"+r"(dst_y), // %1
"+r"(width) // %2
: "r"(shift) // %3
: "memory", "cc", "xmm0", "xmm1", "xmm2");
}
#endif // HAS_CONVERT8TO16ROW_AVX2

2
source/row_neon.cc
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@ -3963,7 +3963,7 @@ void Convert16To8Row_NEON(const uint16_t* src_y,
uint8_t* dst_y,
int scale,
int width) {
int shift = 15 - __builtin_clz((int32_t)scale); // Negative shl is shr
const int shift = 15 - __builtin_clz((int32_t)scale); // Negative shl is shr
asm volatile(
"vdup.16 q2, %3 \n"
"1: \n"

14
source/row_neon64.cc
View File

@ -3983,8 +3983,8 @@ void InterpolateRow_NEON(uint8_t* dst_ptr,
ptrdiff_t src_stride,
int dst_width,
int source_y_fraction) {
int y1_fraction = source_y_fraction;
int y0_fraction = 256 - y1_fraction;
const int y1_fraction = source_y_fraction;
const int y0_fraction = 256 - y1_fraction;
const uint8_t* src_ptr1 = src_ptr + src_stride;
asm volatile(
"cmp %w4, #0 \n"
@ -4119,10 +4119,10 @@ void InterpolateRow_16To8_NEON(uint8_t* dst_ptr,
int scale,
int dst_width,
int source_y_fraction) {
int y1_fraction = source_y_fraction;
int y0_fraction = 256 - y1_fraction;
const int y1_fraction = source_y_fraction;
const int y0_fraction = 256 - y1_fraction;
const uint16_t* src_ptr1 = src_ptr + src_stride;
int shift = 15 - __builtin_clz((int32_t)scale); // Negative shl is shr
const int shift = 15 - __builtin_clz((int32_t)scale); // Negative shl is shr
asm volatile(
"dup v6.8h, %w6 \n"
@ -5529,7 +5529,7 @@ void Convert16To8Row_NEON(const uint16_t* src_y,
// 15 - clz(scale), + 8 to shift result into the high half of the lane to
// saturate, then we can just use UZP2 to narrow rather than a pair of
// saturating narrow instructions.
int shift = 23 - __builtin_clz((int32_t)scale);
const int shift = 23 - __builtin_clz((int32_t)scale);
asm volatile(
"dup v2.8h, %w3 \n"
"1: \n"
@ -5591,7 +5591,7 @@ void Convert8To16Row_NEON(const uint8_t* src_y,
// (src * 0x0101 * scale) >> 16.
// Since scale is a power of two, compute the shift to use to avoid needing
// to widen to int32.
int shift = 15 - __builtin_clz(scale);
const int shift = 15 - __builtin_clz(scale);
asm volatile(
"dup v2.8h, %w[shift] \n"
"1: \n"

12
source/row_sme.cc
View File

@ -569,7 +569,7 @@ __arm_locally_streaming void Convert16To8Row_SME(const uint16_t* src_y,
// 15 - clz(scale), + 8 to shift result into the high half of the lane to
// saturate, then we can just use UZP2 to narrow rather than a pair of
// saturating narrow instructions.
int shift = 23 - __builtin_clz((int32_t)scale);
const int shift = 23 - __builtin_clz((int32_t)scale);
int vl;
asm volatile(
"cntb %x[vl] \n"
@ -917,7 +917,7 @@ __arm_locally_streaming static void HalfRow_16To8_SME(uint8_t* dst_ptr,
// 15 - clz(scale), + 8 to shift result into the high half of the lane to
// saturate, then we can just use UZP2 to narrow rather than a pair of
// saturating narrow instructions.
int shift = 23 - __builtin_clz((int32_t)scale);
const int shift = 23 - __builtin_clz((int32_t)scale);
int vl;
asm volatile(
@ -977,8 +977,8 @@ __arm_locally_streaming void InterpolateRow_16To8_SME(uint8_t* dst_ptr,
int scale,
int width,
int source_y_fraction) {
int y1_fraction = source_y_fraction;
int y0_fraction = 256 - y1_fraction;
const int y1_fraction = source_y_fraction;
const int y0_fraction = 256 - y1_fraction;
const uint16_t* src_ptr1 = src_ptr + src_stride;
// y0_fraction == 0 is never called here.
@ -994,7 +994,7 @@ __arm_locally_streaming void InterpolateRow_16To8_SME(uint8_t* dst_ptr,
// 15 - clz(scale), + 8 to shift result into the high half of the lane to
// saturate, then we can just use UZP2 to narrow rather than a pair of
// saturating narrow instructions.
int shift = 23 - __builtin_clz((int32_t)scale);
const int shift = 23 - __builtin_clz((int32_t)scale);
int vl;
asm volatile(
@ -1085,7 +1085,7 @@ __arm_locally_streaming void Convert8To16Row_SME(const uint8_t* src_y,
// (src * 0x0101 * scale) >> 16.
// Since scale is a power of two, compute the shift to use to avoid needing
// to widen to int32.
int shift = __builtin_clz(scale) - 15;
const int shift = __builtin_clz(scale) - 15;
uint64_t vl;
asm volatile(

2
source/row_win.cc
View File

@ -184,7 +184,7 @@ void I444AlphaToARGBRow_SSSE3(const uint8_t* y_buf,
// 32 bit
#else // defined(_M_X64)
// if HAS_ARGBTOUVROW_SSSE3
// ifdef HAS_ARGBTOUVROW_SSSE3
// 8 bit fixed point 0.5, for bias of UV.
static const ulvec8 kBiasUV128 = {